The nano-hertz and milli-hertz stochastic gravitational waves in the minimal clockwork axion model

Xiangwei Yin, Cheng-Wei Chiang, Bo-Qiang Lu +1

The clockwork framework can realize TeV-scale $U(1{)}_{PQ}$ symmetry breaking while generating a large axion decay constant \(f_a\). We propose a minimal clockwork axion model with t…